Question

Problem 2: Serratia marcescens bacteria are used for the production of threonine. The specific oxygen uptake rate of S. marcescens in batch culture is 6 mmol O2 g1 h 2. It is planned to operate the fermenter to achieve a cell density of 50 g 1-1. At the fermentation temperature and pressure, the solubility of oxygen in the culture liquid is 8 x 10-3 kg m3. The concentration of oxygen in the culture liquid is 3 x 10-4 kg m-3. Calculate the minimum value of kla so that the rate of cell metabolism will NOT be limited by mass transfer?

Answer 1

0 used are 1 + 8x103 Given that Serratia marcescens bacteria for the production of threonine. The specific Oxygen uptake rate of s. The given for 902=6X163 mol 02/9.c The maximum cell density; x = 50g|L conc of Oz in the Culture liquid , CAL=8 0.3X163kg pai K La=? The molecular weight of Oz -32 902-6X163 mol O2I9h 1329 lignol in Liooommol 19 molJ36005 = 5.31X162 g/9.5 at a cell densitys 5091L The maximum er requirement ; q 509 1000 LILIKg L 009 = 26.55 The rate of O2 transfer kg/m3.s NA KLa LCTAL-CAL) =kLal8x103. ~0.3x103) kglma =kla (tax103) kg/m3 Kla (0.0077) kg/m3 -2,1 x 104 kg /m3

2 Kla-2.151 As the maximum O2 demand of the Culture is greater then the a transfer rate in the fermeter, the system will be limited by mass transfer, Limited mass transferi